Can I Retro Back to Passport 10.3.1.1955?

Further to my previous post, I'm currently on 2267 which has been problematic and BlackBerry doesn't seem at all keen to help out and is currently blaming my carrier for the bugs (Passport was purchased from Shop BlackBerry and update was pushed directly to device from them).

If what BlackBerry tells me is true then going forward won't help at all but 1955 from AT&T worked perfectly. Can I retro back to that version via Sachesi?